M*CARBO Brotherhood

Guide To A Perfect Sub2k Detailed Summary


Thanks, I’m the 9mm. Priority is making the buffer tube, if that’s what we call it, more comfortable against my cheek for rapid strings. Thanks for the detailed response!


@PattonWasRight If you want the firearm to fold, you have less than 1/8 inch to work with. And unless your sight is mounted unusually high, anything much thicker than that will keep you from getting low enough for a clear sight picture. In short, the MCarbo bolt tube cover ($14.95) is probably your best bet.



The MCARBO Bolt Tube Cover is really a nice one and will help with that issue and still allows S2K to close and latch.


Good read, thanks. I didn’t know the Picatinny rails weren’t flat. That explains why my red dot isn’t perpendicular. That’s pretty lame you have to file them flat. Sorry, but Kel Tec needs to pay attention to the details. Sorry about the rant.


@Scooter Nope your good…many of us wonder the same thing!


@Scooter Is your mount a Weaver type or Picatinny ? Weaver uses a “U” shaped screw through the mount. Picatinny uses a square screw. You can use a Weaver on a Picatinny rail but it will be loose. No problem when using a Pic mount on Kel-Tec’s upper rail. They are made to different specs.


That is one reason I have not took the plunge. Think the concept is awesome. Like how it folds, easy to carry in a back pack. To be honest the gun sucks bone stock. You add all the aftermarket goodies to make it a decent shooter and that $300-$500 initial gun investment (depending on sales) starts to add up quickly. I’m all about customizing my guns. I know a lot of it is to keep costs down, but do we really need a sh**ty 8-10lb gritty trigger from the factory on a 9mm or. 40 cal? Looking forward to the Joint effort with Keltec and M*CARBO on their new release. See what comes of that.
Sorry didn’t mean to get off topic.


Many people have been putting their upgrades to the Sub2K so I figured I would too.

M*CARBO Performance Pack, Muzzle Break, Shock Buffer, Recoilless Charging handle, Heavier Bolt from KelTec, Recoil Pad from American Tactical Industries (ATI), Hand Grip from Magpul, Red Dot from Primary Arms, Red Dot Mount from American Defense and a 31 round Factory magazine with the +20 magazine Goliath mag extension from Taylor Freelance.
Oh Yeah, I also reduced the Trigger Weight from 8 lbs 3 oz to 3 lbs 10 oz by also polishing the hammer and sear.
Here is a picture of what it looks like!

See what you can do with this if you try! Now, If I can shoot as good as it looks.
John Bacon


@jabacon52 so the 20 round goliath extension on a 31 round gives a 51 round capacity to that magazine? Any issues with the spring or follower inside?


Taylor will send you a new spring (Wolff) and you can use the factory follower.

It will make the Happy Stick and Really Happy Happy Stick!

BTW - No issues!


Duuuuuuuuuuude! I am gonna get one! Thank you for that VERY cool accessory. One more question if you please. How long is the extended happy stick? I still need it to fit in the 18.5" available in the case.


The OAL is 12”.
Go to www.taylorfreelance.com and look for the Goliath Mag Extender.

I recommend the Aluminum one and not the Polymer one because it can crack!

If your case is 18.5” Long then it must be from Unique Cases because the one from Keltec is too short.

Also, these extenders meet USPSA for PCC.

If you want to do what I did, go to the websites of the companies I mentioned.

If you get the Heavier Bolt from Keltec, I recommend that your Debur the slot where the Charging Handle goes and Sand down the diameter of the Heavier Bolt because it is the same size of the tube and will cause drag.

If you have any other questions in regards to modifying the Sub 2000, please ask, I will help!



It’s a Picatinny mount. I filed the rail flat and now it mounts perpendicular not leaning to the left. The “Leaning Red Dot of Kel Tec” is no more. Ha ha


I tested some red dot mounts and the peaked rail is just dumb. You can tilt it left or right, either side of the rail’s “hill.”

All the rails that the mount base would contact need to be made flat. What technique did you use to sand? I don’t want to over do it but since I have a Dremel I’m a gun Smith right?



I would first use a small hand file. If you use a Dremel tool I would set the variable speed all the way down and just slowly hit that peak bringing it down a little at a time till movement in mount stops. The finer the file or sanding drum bit the less course the marks will be in the plastic. Harbor Freight Tools sells diamond drum bits for a Dremel tool that are much finer than a sanding drum bit. They work really well for taking small amounts of material off at a time.


lol - yup, that and a flat tip screwdriver lol I just used a small, sharp, hand file and layed it flat length wise on the rail (not across) and held the whole file in my fingertips (not just the ends) and just pushed it along a few times. Didn’t take a lot :+1: I used to do a lot of ski base tuning and a “file card” or some kind of stiff bristled brush is very helpful when filing plastics to clear the teeth.


After filing or sanding, use a black Sharpie to return the plastic to it’s original color.


AS @triggerhappy and others have mentioned great job. Glad to see some efforts from others have helped!!!


Great write up and adding upgrades is of course the most fun one can have with any firearm other than range time. Thanks for the adaptive tactical recoil pad tip. I’m aware of the ATI limitations both aesthetically and in terms of tearing. Can any of the brothers enlighten me as to whether you can leave the ATI recoil pad on when removing the stock for cleaning or maintenance. In other words can one access the buffer release button without removing that pad ?
And is it attached without any screws just by separating the flanges and pushing it on to the end of the butt stock? In that case even if it doesn’t stay on when removing the butt stock it seems like it’s easy to remove

I don’t find the 9 mm recoil to be noticeable at the range but I don’t like the red lines on my pec – shoulder groove that I see at home with shirt off…



I have seen many images where people have put zip ties onto the ATI recoil pad because it falls of once cracked. Or just to hold it in place as I have read that it can slide around a little bit. That is why I like the 2 screws to hold that bad boy on and in place. I can still take apart and reassemble with no issues. The only caveat which is truly very very minor, is to pop the buffer assembly into the stock before sliding onto the buffer tube. You can see how nice it looks. And I tell you it does a shoulder nicely.